High index low density glass

Abstract

A glass comprising greater or equal to 30.0 mol % SiO2, the glass being free of iron, lead, antimony ant tantalum oxides, and having a refractive index nd greater than or equal to 1.75 and a linear thermal expansion coefficient α20-300, in the temperature range 20-300° C., that is less than or equal to about 65×10−7 K−1.

What is claimed is: 
     
       1. A glass comprising: from 30.0 mol % to 45 mol % SiO 2 , from 0.5 mol% to 15 mol% Al 2   0   3 , from 10 mol % to 20 mol % TiO 2 , from 3 mol % to 20 mol % ZnO, from 0.3 mol % to 10 mol % La 2 O 3 , and from 5 mol % to 20 mol % MgO+CaO+SrO+BaO, wherein the glass is free of iron, lead, antimony and tantalum oxides, said glass having a refractive index n d  greater than or equal to 1.75 and a linear thermal expansion coefficient α 20-300 , in the temperature range 20° C. to 300° C., that is less than or equal to 65×10 −7  K −1 . 
     
     
       2. The glass according to  claim 1 , comprising from 30 to 35 mol % of the SiO 2 , from 10 to 15 mol % of the Al 2 O 3 , from 15 to 20 mol % of the TiO 2 , from 15 to 20 mol % of the ZnO, from 5 to 10 mol % of the La 2 O 3 , and from 10 to 15 mol % of the MgO+CaO+SrO+BaO. 
     
     
       3. A glass article comprising the glass of  claim 1 . 
     
     
       4. A system comprising the glass article of  claim 3 , wherein the system is an optical system, an information storage device, or an augmented reality device. 
     
     
       5. A glass comprising:
 from 30.0 mol % to 45 mol % SiO 2 , from 0.5 mol% to 15 mol% Al 2 O 3 , from 10 mol % to 20 mol % TiO 2 , from 3 mol % to 20 mol % ZnO, from 0.3 mol % to 10 mol % La 2 O 3 , and from 5 mol % to 20 mol % MgO+CaO+SrO+BaO, wherein said glass having a refractive index n d  greater than or equal to 1.75, a linear thermal expansion coefficient (α 20-300 ) that is less than or equal to 80×10 −7  K −1 , and a Young's elastic modulus (E) that is greater than or equal to 100 GPa. 
 
     
     
       6. The glass according to  claim 5 , comprising from 30 to 45 mol % SiO 2 , from mol % from 0.5 mol % to 15 mol % Al 2 O 3 , from 10 to 20 mol % TiO 2 , from 5 to 20 mol % ZnO, from 5 to 10 mol % (La 2 O 3 +Y 2 O 3 ), and from 5 mol % to 15 mol % MgO+CaO+SrO+BaO. 
     
     
       7. The glass according to  claim 5 , said glass being free of iron, lead, antimony and tantalum oxides. 
     
     
       8. The glass according to  claim 5 , wherein the glass has a linear thermal expansion coefficient in the temperature range 20° C. to 300° C., α 20-300 , of less than or equal to 65×10 −7  K −1 , and a Young's elastic modulus (E) that is greater than or equal to 110 GPa. 
     
     
       9. The glass according to  claim 5 , wherein the glass has a linear thermal expansion coefficient in the temperature range 20° C. to 300° C., α 20-300 , of less than or equal to 60×10 −7  K −1 , and a Young's elastic modulus (E) that is greater than or equal to 115 GPa. 
     
     
       10. A glass composition comprising:
 from 30.0 mol % to 45 mol % SiO 2 , from 0.5 mol% to 15 mol% Al 2 O 3 , from 10 mol % to 20 mol % TiO 2 , from 3 mol % to 20 mol % ZnO, from 0.3 mol % to 10 mol % La 2 O 3 , and from 5 mol % to 20 mol % MgO+CaO+SrO+BaO, and substantially free of the compounds of Fe, Pb, Sb, and Ta, 
 
       wherein the glass composition has:
 a refractive index n d  that is greater than or equal to 1.75 and a thermal expansion coefficient that is less than or equal to 65.0*10 −7  K −1  in the temperature range 20° C. to 300° C. 
 
     
     
       11. The glass composition of  claim 10 , wherein the glass composition further comprises
 greater than or equal to 30 mol % and less than or equal to 35 mol % of the SiO 2 , 
 greater than or equal to 10 mol % and less than or equal to 20 mol % of the MgO+CaO+SrO+BaO (MgO+CaO+SrO+BaO), 
 greater than or equal to 10 mol % and less than or equal to 20 mol % of the TiO 2 ; and 
 greater than or equal to 10 mol % and less than or equal to 20 mol % of the ZnO. 
 
     
     
       12. The glass composition of  claim 10 , wherein the glass composition comprises:
 greater than or equal to 14 mol % and less than or equal to 16 mol % of the TiO 2 , 
 greater than or equal to 11 mol % and less than or equal to 15 mol % of the MgO+CaO+SrO+BaO; and greater than or equal to 16 mol % and less than or equal to 19 mol % of the ZnO. 
 
     
     
       13. The glass composition of  claim 10 , wherein the glass composition further comprises:
 less than or equal to 15 mol % of the Al 2 O 3 , 
 less than or equal to 8.5 mol % of the La 2 O 3 , and 
 less than 5 mol % Nb 2 O 5 , ZrO 2 , or both. 
 
     
     
       14. The glass composition of  claim 10 , wherein the glass composition is substantially free of bismuth (Bi). 
     
     
       15. The glass composition according to  claim 10 , wherein the glass composition has a thermal expansion coefficient that is less than or equal to 60.0*10 −7  K −1  in the temperature range 20° C. to 300° C.